Sliding action electrical switch with ramp portions between contacts and insulating strips

ABSTRACT

The illustrated switch comprises an insulating carriage which is slidable longitudinally within a casing. The carriage is arranged to be actuated by a pin which projects into an opening in the carriage through a slot in the casing. In this case, the pin is movable along a curved path and is slidable in the opening, which is laterally elongated. A contactor is mounted on the carriage and is provided with three contact points which are engageable with three contact strips secured to an insulating support on the casing. A spring is provided to bias the contactor toward the contact strips. The strips extend parallel to the path of movement of the contactor and are disposed along laterally spaced lines. The line of the first strip extends between the lines of the second and third strips. Two terminals are connected to the first strip and the second and third strips, which are connected together. The switch has an off position in which the first contact point engages the first strip, while the second and third contact points engage insulating bosses or projections disposed opposite the ends of the second and third strips. Upon movement of the contactor, the second and third contact points move smoothly from the insulating bosses into substantially simultaneous engagement with the ends of the second and third strips, which are provided with inclined ramp portions. Throughout a range of movement of the carriage, the three contact points engage the three contact strips.

United States Patent [1 1 Raab 45 ]March 20, 1973 Primary ExaminerRobert K. Schaefer Assistant Examiner-Robert A. Vanderhye AttorneyBurmeister, Palmatier & Hamby [5 7] ABSTRACT The illustrated switch comprises an insulating carriage which is slidable longitudinally within a casing. The carriage is arranged to be actuated by a pin which projects into an opening in the carriage through a slot in the casing. In this case, the pin is movable along a curved path and is slidable in the opening, which is laterally elongated. A contactor is mounted on the carriage and is provided with three contact points which are engageable with three contact strips secured to an insulating support on the casing. A spring is provided to bias the contactor toward the contact strips.

The strips extend parallel to the path of movement of the contactor and are disposed along laterally spaced lines. The line of the first strip extends between the lines of the second and third strips. Two terminals are connected to the first strip and the second and third strips, which are connected together. The switch has an off position in which the first contact point engages the first strip, while the second and third contact points engage insulating bosses or projections disposed opposite the ends of the second and third strips. Upon movement of the contactor, the second and third contact points move smoothly from the insulating bosses into substantially simultaneous engagement with the ends of the second and third strips, which are provided with inclined ramp portions. Throughout a range of movement of the carriage, the three contact points engage the three contact strips. 9

2 Claims, 9 Drawing Figures 154] SLIDING ACTION ELECTRICAL SWITCH WITH RAMP PORTIONS BETWEEN CONTACTS AND INSULATING STRIPS [75] Inventor: Andrew F. Raab, Morton Grove, Ill.

[73] Assignee: Indak Manufacturing Corp.,

Northbrook, Ill.

[22] Filed: June 4, 1971 [21] Appl. No.: 150,037

[52] US. Cl ..200/16 C, ZOO/61.86, 200/164,

[51] Int. Cl ..H01h 15/04, I-IOlh 9/06, l-10lh 3/50 [58] Field of Search .200/16 D, 16 C, 166 SD, 61.85,

I 200/6l.86, 164, 16 R, 166 BI-l [56] References Cited UNITED STATES PATENTS 3,225,150 12/1965 I-Iershberger ..200/16 C X 3,462,564 8/1969 Bedocs ..200/16 C 3,223,794 12/1965 Hoy et al. ..200/16 C 2,937,245 5/1960 Long ..200/16 C 3,306,994 2/1967 Bassett ..200/16 D 3,165,598 1/1965 McClure ..200/166 SD UX 3,454,735 7/1969 Wilde ..200/166 SD 2,365,120 12/1944 Thirlwell ..200/166 SD UX 3,499,126 3/1970 Jones et a1. ..200/16 R 3,051,801 8/1962 Tranbarger et a1 ..200/61 .86

2,912,873 11/1959 Little ..200/6L86 UX 3,072,757 1/1963 Gluck ..200/16 D i I 5.1211: g 7 58 I6 52 14 VM I '12, I

IIIJIIII 111/1 III/I PATENTEnmRzoma SHEET 10F 2 /NVENTOI2 yew .7 Pazzb SLIDING ACTION ELECTRICAL SWITCH WITII RAMP PORTIONS BETWEEN CONTACTS AND INSULATING STRIPS This invention relates to an electrical switch which will find many applications but is especially well suited for certain uses on automobiles or other vehicles.

One object of the present invention is to provide a sliding action electrical switch which has an operating member or carriage which is movable from an off position and then through an extensive range of movement in which the switch is closed.

A further object is to provide a switch of the foregoing character which is capable of carrying and interrupting a high electrical current, while affording extremely long and dependable service.

Another object is to provide a new and improved sliding action switch which is arranged to be actuated by a pin or other member which is an element of a mechanism adapted to control other functions in addition to operating the switch.

A further object is to provide a switch which is highly efficient and reliable, yet is compact and inexpensive.

To achieve these objectives, the switch of the present invention may comprise an insulating carriage which is slidable along a predetermined path within a casing. The carriage is adapted to be operated by a pin or the like which extends through a longitudinal slot in the casing and into an opening in the carriage. Such opening may be laterally elongated to provide for sliding movement of the pin in the opening. In this way, the pin may be movable along a curved path. The carriage supports a contactor having three contact points which are engageable with three fixed contact strips. The casing is provided with insulating means to support the strips.

Preferably, the first strip extends along a line which is disposed between and parallel to the lines of the second and third strips. It is preferred to provide insulating projections or bosses which are engaged by the second and third contact points when the contactor is in its OFF position. The second and third contact points are movable smoothly into engagement with the ends of the second and third strips, which are preferably provided with inclined ramps. The second and third strips are preferably connected together so that the making and breaking of the current occurs at both the second and third strips. Preferably, the first strip is retained between the insulating projections and thus is prevented from moving laterally. The ramp elements on the second and third strips are preferably retained in openings formed in the insulating supports.

Further objects, advantages and features of the present invention will appear from the following description, taken with the accompanying drawings, in which:

FIG. 1 is a diagrammatic plan view showing a switch to be described as an illustrative embodiment of the present invention, the switch being shown in connection with a heater control mechanism for an automobile or the like.

FIG. 2 is a fragmentary front view of the heater control mechanism.

FIG. 3 is a vertical section, taken generally along the line 3-3 shown in both FIGS. I and 2.

FIG. 4 is an enlarged vertical section, taken along the line 4-4 in FIG. 1.

FIG. 5 is a bottom view of the switch with the terminal head removed, the view being taken generally as indicated by the line 5-5 in FIG. 4.

FIGS. 6 and 7 are top and bottom views of the terminal head, detached from the switch.

FIG. 8 is an exploded or disassembled perspective view showing the carriage, the contactor, and the contactor spring.

FIG. 9 is a fragmentary elevational section, taken generally along the broken line 99 in FIG. 6.

As just indicated, the drawings illustrate an example of the present invention as embodied in a switch 10, intended particularly for use in connection with a heater control mechanism 12 for an automobile or some other vehicle. However, it will be understood that the switch may have many other applications.

As shown, the heater control mechanism 12 comprises a control lever 14 which is movable horizontally from an OFF position to a FLOOR position and then to a DEFROST position. It will be seen that the OFF and DEFROST positions are at the opposite ends of the range of movement of the lever 14, while the FLOOR position is at an intermediate point. The switch 10 functions to deenergize the blower motor for the heater when the lever 14 is in its OFF position. The switch 10 closes the circuit for the blower motor when the lever 14 is moved to the FLOOR position. The closed circuit is maintained when the lever 14 is moved to its DEFROST position.

It will be understood that the lever 14 also operates an air damper or valve which directs most of the heated air to the floor of the vehicle when the lever 14 is in the FLOOR position. The heated air is directed to the windshield when the lever 14 is in its DEFROST position.

The air damper or valve may be operated by a lever 16 which is swingable about a pivot 18. The control lever 14 is also swingable about the pivot 18, but is also slidable relative to the pivot. Thus, the lever 14 is formed with a longitudinal slot 20 in which the pivot 18 is slidably received.

As the lever 14 is swung horizontally, it is caused to slide longitudinally by a cam track 22 adapted to be followed by a pin 24 on the lever 14. The purpose of the sliding movement is to minimize the protrusion of the lever 14, relative to the dashboard of the automobile. Such protrusion is maintained substantially constant by the cam track 22, which is curved rearwardly along its central portion, as will be evident from FIG. 1. Thus, the lever 14 is shifted rearwardly relative to the pivot 18 as the lever is swung from either end of its range into the central portion of its range of movement. This will be clearly evident from FIG. 1 in which various positions of the lever are shown in broken lines.

Because of the sliding movement of the lever 14, a pin-and-slot connection is preferably employed to connect the lever 14 to the lever 16. In this case, the lever 16 carries a pin 26 which is slidably received in a longitudinal slot 28 formed in the lever 14. The slot 28 is shown as a reduced continuation of the slot 20.

A friction device is preferably employed to retain the lever 14 in any position to which it may be adjusted, and to prevent any rattling of the lever. As shown in FIG. 3, such friction device comprises a spring-pressed member 30 which is carried by the lever 14 and is slidable along a fixed flange 32. The member 30 may be formed on one end of a leaf spring 34 which presses the member 30 against the flange 32.

As will be explained in greater detail presently, the switch is adapted to be operated by the pin 26 on the lever 16. Thus, the switch 10 has a casing 40 which is formed with a slot 42 through which the pin 26 projects into the casing 40. As shown, the casing 40 is generally in the form of a rectangular box having a top wall 43, two elongated side walls 44 and 46, and end walls 48 and 50. The casing 40 may be made of metal or any other suitable material. The bottom of the casing 40 is closed in a manner to be described presently.

Within the casing 40, a carriage 52 is slidable along a predetermined path. In this case, the carriage 52 is slidable longitudinally and is guided by the longitudinal side walls 44 and 46, as well as the top wall 43.

The carriage 52 is adapted to be operated by the pin 26, which preferably is received in a laterally elongated opening 54 formed in the carriage. The elongated opening 54 provides for lateral sliding movement of the pin 26, relative to the carriage 52, as the pin 26 is moved along its curved path.

As shown, the carriage 52 is formed with prongs or extensions 56 at its opposite ends adapted to move outwardly through openings 58 in the opposite ends of the casing 40. The extensions 56 make it easy to adjust the position of the carriage 52 during the assembly of the heater control mechanism 12.

A conductive contactor 60 is preferably mounted on the carriage 52 and is engageable with fixed contact elements 62 supported on the casing 40. The carriage 52 is preferably made of an insulating material, such as a suitable plastic, while the contactor 60 is preferably made of a good conductor, such as copper for example.

The fixed contact elements 62 are preferably supported by insulating means, mounted on or forming a part of the casing 40. As shown, the bottom of the easing 40 is closed by an insulating board or member 64, which may be made of a suitable plastic material. The insulating board 64 may be secured to the casing 40 by any suitable means illustrated as comprising a plurality of tabs 66 extending through slots 68 in the edge portions of the board 64, and bent against the lower side of the board. The tabs 66 are formed on the walls of the casing 40.

The contactor 60 may assume various forms but is shown as a conductive plate 70 having locating tabs or prongs 72 bent upwardly therefrom. Openings 74 are preferably formed in the carriage 52 to receive the prongs 72 so that the contactor 60 will be connected to the carriage for movement therewith. The contactor 60 may have an opening 76 therein opposite the opening 54 in the carriage 52, and of a sufficient size to obviate any contact between the pin 26 and the contactor 60.

It is preferred to provide means for biasing the contactor 60 toward the contact elements 62. As shown, a spring 78 is interposed between the carriage 52 and the contactor 60. The spring 78 is illustrated as a thin leaf spring which is bowed or bent initially so that the spring will exert force against the contactor 60 when the spring is compressed between the contactor and the carriage 52. It will be seen that the spring 78 is formed with slots 80 in its opposite ends to receive the locating tabs 72 on the carriage 52 so that the spring will be retained in alinement with the contactor 60. A central opening 82 is preferably formed in the spring 78 opposite the opening 54 in the carriage 52 and of a sufficient size to obviate any contact between the spring 78 and the pin 26.

In this case, the contactor 60 is formed with three contact points 84, and 86 which project downwardly from the contactor and preferably are formed integrally with the metal plate 70. The contact points 84, 85 and 86 are smoothly rounded in shape. It will be seen that the first contact point 84 is centrally disposed near one end of the contactor 60. The second and third contact points 85 and 86 are disposed near the opposite end of the contactor and are spaced laterally in opposite directions from the longitudinal line along which the first contact point 84 is located.

The fixed contact elements 62 may assume various forms, but are illustrated as three contact strips 88, and 91 mounted on the insulating board or support 64. In the illustrated construction, the second and third contact strips 90 and 91 are connected together by means of a conductive crossbar or member 92, which preferably is formed integrally with the strips 90 and 91.

The three contact strips 88, 90 and 91 extend longitudinally and are thus parallel to the path of the contactor 60. It will be seen that the strips 88, 90 and 91 are disposed along laterally spaced lines. The line of the first contact strip 88 corresponds to that of the first contact point 84 and thus is centrally disposed in the illustrated construction. The lines of the contact strips 90 and 91 correspond to those of the contact points 85 and 86 and are spaced on opposite sides of the line of the strip 88.

In this case, two terminals 94 and 95 are suitably mounted on the insulating support 64, as by means of rivets 96 and 97. It will be seen that the rivet 96 is employed to secure the first contact strip 88 to the insulating support 64. The second rivet 97 extends through the crossbar 92 and thus is employed to secure the second and third contact strips 90 and 91 to the insulating support 64. The contact points 84, 85 and 86 hold the contactor 60 away from the rivets 96 and 97 so that the contactor does not engage the rivets.

The longitudinal extent of the first contact strip 88 is such that this contact strip is engaged by the first contact point 84 throughout the range of movement of the contactor 60. However, the second and third contact points 85 and 86 are out of engagement with the second and third contact strips 90 and 91 when the contactor 60 is moved to its OFF position, corresponding to the OFF position of the lever 14. In FIGS. 5 and 9, the contactor 60 is shown in its OFF position corresponding to the lefthand end of the range of movement of the carriage 52.

When the contactor 60 is moved 'to the right from the position shown in FIGS. 5 and 9, the contact points 85 and 86 engage the end portions of the contact strips 90 and 91. Such engagement with the two strips is substantially simultaneous. Thus, the contact points 85 and 86 provide a double making and breaking action with the contact strips 90 and 91. This has the effect of distributing the wear and erosion on the contact points 85 and 86 and the contact strips 90 and 91. Accordingly, the switch is enabled to handle heavy electrical currents while providing an extremely long life.

To provide for smooth and efficient operation of the switch, it is preferred to provide insulating projections or bosses 98 and 99 on the insulating support 64 for engagement by the second and third contact points 85 and 86 when the contactor 60 is in its OFF position. As will be evident from FIG. 9, the insulating projections 98 and 99 are substantially flush with the contact strips 90 and 91 so that the contact points 35 and 86 will move smoothly and easily between the projections and the contact strips. As shown, the insulating projections 98 and 99 are in the form of semiperforations offset upwardly from the insulating board or support 64. However, the insulating projections may be molded or otherwise formed.

To afford further assurance of smooth action, the end portions of the contact strips 911 and 91 are preferably formed with inclined ramp elements 100 and 1111 adapted to be engaged by the contact points 85 and 86 as they move between the insulating projections 98 and 99 and the contact strips 90 and 91. As shown in FIG. 9, the ramp elements 101) and 101 are also preferably employed to locate the ends of the contact strips 911 and 91. Thus, the ramp elements 100 and 101 are preferably bent downwardly from the ends of the contact strips 90 and 91 and are received in locating openings 1112 and 103 formed in the insulating support 64. In this way, lateral movement of the contact strips 90 and 91 is prevented so that the contact strips will not rotate about the rivet 97,

Lateral movement of the first contact strip 88 is preferably prevented by confining it between the insulating projections 98 and 99, as clearly shown in NO. 6. In this way, rotation of the contact strip 8 about the rivet 96 is prevented.

As the contactor 60 is moved to the right from its OFF position, shown in FIGS. 5 and 9, the contact points 85 and 86 ride smoothly from the insulating projections 98 and 99 and along the ramp elements 100 and 101 and thus are brought into engagement with the contact strips 90 and 91 so as to close the circuit controlled by the switch. The switch remains closed as the contactor 611 is moved to the right through the remainder of its range. Thus, the switch is closed when the control lever 14 is in its FLOOR and DEFROST positions, shown in FIGS. 1 and 2.

When the contactor 611 is returned to its OFF position, the contact points 85 and 86 break contact simultaneously, or nearly so, with the contact strips 90 and 91. This action has the effect of equalizing the electrical erosion on the contact points and the contact strips so that the life of the switch is greatly increased.

The three contact points 84, 85 and 86 support the contactor 60 at all times. Due to the three point contact, there is never any tendency for the contactor 60 to rock or teeter relative to the contact elements.

The curved slot $2 in the casing 411 allows for the movement of the operating pin or member 2 15 along a curved path. The curved movement of the pin is also accommodated by the laterally elongated opening 54 in the carriage 52. This formation of the carriage allows the pin to slide laterally as it moves the carriage longitudinally.

Various modifications, alternative constructions and equivalents may be employed, as will be evident to those skilled in the art.

lclaim:

1. An electrical switch, comprising a casing,

an insulating carriage slidable linearly within said casing along a predetermined path,

first, second and third contact strips disposed opposite said carriage and extending parallel to the path thereof,

said casing including insulating means for supporting said contact strips,

said strips being disposed along parallel lines which are spaced apart laterally,

the line of said first strip being disposed between the lines of said second and third strips,

conductive means connected between said second and third strips,

a first terminal connected to said first strip,

a second terminal connected to said second and third strips,

and a contactor mounted on said carriage and engageable with said strips,

said contactor including first, second and third contact points projecting therefrom toward said strips,

said first contact point being slidably engaged with said first strip,

said second and third contact points being slidable into and out of engagement with said respective second and third strips as said carriage is moved in opposite directions within said casing,

said second and third strips including end portions for initial engagement by said second and third contact points,

said insulating means including insulating projections adjacent said end portions and substantially flush with said second and third strips,

said end portions of said second and third strips including ramp elements bent at an inclined angle therefrom for engagement by said second and third contact points whereby said second and third contact points are enabled to slide smoothly between said insulating projections and said ramp elements on said end portions of said second and third strips,

said insulating means having openings adjacent said insulating projections for receiving and locating said ramp elements.

2. A switch according to claim 1,

in which said first contact strip includesan end portion fitted between said insulating projections and thereby restrained against lateral movement. 

1. An electrical switch, comprising a casing, an insulating carriage slidable linearly within said casing along a predetermined path, first, second and third contact strips disposed opposite said carriage and extending parallel to the path thereof, said casing including insulating means for supporting said contact strips, said strips being disposed along parallel lines which are spaced apart laterally, the line of said first strip being disposed between the lines of said second and third strips, conductive means connected between said second and third strips, a first terminal connected to said first strip, a second terminal connected to said second and third strips, and a contactor mounted on said carriage and engageable with said sTrips, said contactor including first, second and third contact points projecting therefrom toward said strips, said first contact point being slidably engaged with said first strip, said second and third contact points being slidable into and out of engagement with said respective second and third strips as said carriage is moved in opposite directions within said casing, said second and third strips including end portions for initial engagement by said second and third contact points, said insulating means including insulating projections adjacent said end portions and substantially flush with said second and third strips, said end portions of said second and third strips including ramp elements bent at an inclined angle therefrom for engagement by said second and third contact points whereby said second and third contact points are enabled to slide smoothly between said insulating projections and said ramp elements on said end portions of said second and third strips, said insulating means having openings adjacent said insulating projections for receiving and locating said ramp elements.
 2. A switch according to claim 1, in which said first contact strip includes an end portion fitted between said insulating projections and thereby restrained against lateral movement. 